package redis.clients.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public interface Hashing {
    public static final Hashing MURMUR_HASH = new MurmurHash();
    public ThreadLocal<MessageDigest> md5Holder = new ThreadLocal<MessageDigest>();

    public static final Hashing MD5 = new Hashing() {
	public long hash(String key) {
	    return hash(SafeEncoder.encode(key));
	}

	public long hash(byte[] key) {
	    try {
		if (md5Holder.get() == null) {
		    md5Holder.set(MessageDigest.getInstance("MD5"));
		}
	    } catch (NoSuchAlgorithmException e) {
		throw new IllegalStateException("++++ no md5 algorythm found");
	    }
	    MessageDigest md5 = md5Holder.get();

	    md5.reset();
	    md5.update(key);
	    byte[] bKey = md5.digest();
	    long res = ((long) (bKey[3] & 0xFF) << 24)
		    | ((long) (bKey[2] & 0xFF) << 16)
		    | ((long) (bKey[1] & 0xFF) << 8) | (long) (bKey[0] & 0xFF);
	    return res;
	}
    };

    public long hash(String key);

    public long hash(byte[] key);
}